A control program, which describes a control operation of a vehicle-mounted control device that is mounted in a vehicle, is stored in a nonvolatile memory such as a flash memory in a microcomputer. In addition, data such as an initial value that is used in the control program is also stored in the nonvolatile memory. Typically, the program or data is not changed after putting a vehicle on the market. However, updating of the control program or data is performed when a bug is detected, or so as to provide a better service.
With regard to an update process of the control program or data of the vehicle, the vehicle is brought into a shop, and rewriting is performed in the shot. However, recently, a method of carrying out the rewriting through a wireless communication over a mobile telephone network that is an infrastructure on an outer side of the vehicle.
For example, in PTL 1, an information management base station apparatus on an outer side of a vehicle transmits an update request to a stopped vehicle through a wireless communication device that is mounted in the vehicle. The vehicle, which receives the update request, wakes up from a sleep state and activates a vehicle-mounted control device that is mounted in the vehicle, and writes an update program, which is transmitted from the information management base station, in the vehicle-mounted control device.
In addition, PTL 2 discloses the following configuration. An external tool and a writing device that is mounted in a vehicle are connected through a communication cable. An update program, which is transmitted from the external tool, is stored in the writing device. The update program is written in the vehicle-mounted control device from the writing device in a state in which the communication cable is removed. In PTL 2, a communication is not necessary during writing, and thus the communication cable can be connected to another vehicle to store the update program in the recording device. As a result, with regard to writing time, shortening of the writing time is realized when considering that the writing is possible without a communication with an outer side and thus writing time can be shortened, and the writing process with respect to the vehicle and a storage process of the update program with respect to the other vehicle through the communication cable can be simultaneously executed.